Wireless telephones, such as but not limited to wireless telephones that communicate using Code Division Multiple Access (CDMA) spread spectrum modulation techniques, communicate over the air with system infrastructure using wireless telephone over-the-air communication protocols, e.g., the CDMA protocols known as IS-95A, IS-95B, and IS-2000. The system infrastructure, which can include base stations (BTS), base station controllers (BSC), and other components, connects the wireless telephone to another communication device, such as a through land line or another wireless communication system.
In the case of CDMA, voice data is sent over the air in packets that are collected by the infrastructure and assembled into a voice stream, transparently to the speakers who are talking to each other. As might be expected, the over-the-air protocol is tailored to optimize wireless communication. For instance, to maximize over-the-air capacity, the over-the-air protocol contains a minimum of signalling information, and the size of a voice data packet is relatively small.
With the growth of the Internet, computer-to-computer communication using Internet Protocols (IP) has become ubiquitous. Furthermore, it has become desirable not only to facilitate computer data communication using IP, but to facilitate voice communication using IP as well. As but one advantage afforded by using IP in a telephony infrastructure, much hardware such as switches can be eliminated, and existing computers and software can be used instead, reducing cost. To this end, so-called voice over IP (VOIP) has been introduced.
To support VOIP, a communication device must have, among other requirements, IP capability, i.e., the device must itself be able to communicate using IP, and it must have an IP address.
The present invention critically observes, however, that requiring a wireless telephone to use VOIP diminishes over-the-air capacity because VOIP is not necessarily designed to maximize such capacity. Instead, VOIP accounts for design considerations that are not necessarily related to wireless telephony. As an example, the data packet size of VOIP is relatively large, compared to the packet size used throughout the wireless communication industry such as in wireless telephones using over-the-air protocols such as IS-95. Indeed, a typical packet size in the IS-95 protocol is less than the size of a single packet header employed in a typical IP. Moreover, configuring a wireless telephone to communicate using both IP and over-the-air protocols complicates telephone design, adversely strains available resources (e.g., power, computing cycles, coding, and so on), and increases costs.
Nonetheless, the present invention understands that it would be desirable to enable wireless protocol-based communication, such as CDMA, for the over-the-air (OTA) portion of a call, while using an infrastructure that transmits data internally in accordance with IP principles. The present invention further understands that in communicating OTA protocol-carried call set-up data from a wireless telephone to various components inside an IP-enabled telephony infrastructure, it would be preferable to use an existing IP-based call set-up protocol, instead of creating an entirely new protocol. With the above considerations in mind, the present invention provides the solutions disclosed below.